The engine immobiliser system is designed to prevent the vehicle from being stolen. This system uses a transponder key ecu that stores the key codes of authorized ignition keys. If an attempt is made to start the engine using an unauthorized key, the ecu sends a signal to the ecm to prohibit fuel delivery and ignition, effectively disabling the engine.

The transponder key coil receives this signal, the transponder key amplifier amplifies it, and then the signal is transmitted to the ecu. The ecu matches the key's id code with the vehicle's id code, which was previously registered in the ecu and then communicates the results to the ecm using sfi communication.
Engine immobiliser system
How to proceed with troubleshootingPrecaution
If any of following conditions are met,
keep engine idling with a/c on (engine
speed at less than 2000 rpm) for at least 1
minute:
Refrigerant gas has been refilled or a/c parts have
been replaced.
A long time has elapsed since the engine was
stopped.
Notice:
If the engine s ...
Battery current sensor circuit
Description
The battery current sensor installed on the positive (+) battery terminal
detects the amount of current
supplied from the generator.
The battery current sensor changes current to voltage (at the positive (+)
battery terminal) and sends it to
the ecm. The ecm controls th ...
How to proceed with troubleshooting
Hint:
Use these procedures to troubleshoot the key reminder
warning system.
*: Use the intelligent tester.
Vehicle brought to workshop
Inspect battery voltage
Standard voltage:
11 to 14 v
Hint:
If the voltage is below 11 v, recharge or replace the battery
before proceedi ...